Question about Mis-matched offsets.

[Legacy]

Here's the deal, I'm getting some bolt on spacers made for this setup:

F: 16x7J +38 (205/55/16) down to 7J +10 (same tires)
R: 16x8J +38 (225/50/16) down to 8J +15 (same tires)

My question is:

With that setup the rear will stick out 8mm more than the front. I'm gonna go get an alignment and I'm assuming that I'll probably have something like -2 to -2.5 degree camber. On a S13 does the rear require a slightly lower offset to even out with the front?

Like If I even it up with:
7J +10
8J +23

Would the rear be more sunk in than the front? I don't really get how it works. Common sense tells me that evening up the offset in porportion to width would make them fit evenly, unless the body or suspension geometry is different. Also, if there is like a -.5 degree camber difference in the rear. Like -2 in the front and -2.5 in the rear, it would probably make the wheels pefectly evenly flushed right?

Thank in Advance,
Dave

BTW... sorry, I hate asking offset questions... so repetitive.